1. Field of the Invention
The present invention relates to a movable vacuum forming apparatus used in a press machine for molding a laminated plate, rubber or resin and capable of forming a vacuum space which can deal with a dimensional change in a pressing direction.
2. Prior Art
A press apparatus or a heated press apparatus has been conventionally used widely in laminating, press-contacting or molding plate, powder, fiber, foil or the like of organic substance, inorganic substance, metal or the like or composite materials of these or in rubber molding, resin molding or the like.
According to such a press apparatus, when it is intended to increase an adherence degree of a work or remove remaining gas bubbles, pressing needs to carry out in a vacuum state. Further, when heating is needed in laminating or molding a work, pressing in a vacuum state is similarly needed in order to increase an adherence degree or a density by preventing gas bubbles produced by heating from remaining, preventing insulation failure by remaining gas bubbles in electronic parts or the like, or preventing wiring patterns from being oxidized by oxygen in the atmosphere.
In order to achieve the above-described object, according to a conventional press apparatus, a hermetically-sealed space is formed by providing a single piece of cylindrical body between upper and lower press plates. Further, packings made of synthetic rubber are interposed between the upper and lower press plates and upper and lower ends of the cylindrical body and the packings are made to follow movement in the up and down direction by pressing and a change in a height of a fabricated composite material within a range of elasticity of rubber.
However, according to such a conventional constitution, there is provided only follow-up performance within a range of elasticity of the synthetic rubber and therefore, there poses a problem that an exclusive cylindrical body having a different height must be fabricated to deal with a small difference in the height of the work or a variation in the height. Further, since the cylindrically body is directly applied with compression load of pressing, there poses a problem that deformation or destruction of the cylindrical body is liable to cause.
Further, there also is a vacuum press machine of a house type confining a total of the press apparatus in a vacuum chamber, in this case, there pose problems that the cost is high, the installation space is large, time is taken for vacuuming when the volume of the vacuum chamber is large, the maintenance is laborious, or a conventional general purpose open press machine cannot be diverted thereto.
It is an object of the invention to improve the above-described drawbacks of the conventional technology.
In order to achieve the above-described object, according to an aspect of the invention, there is provided a movable vacuum forming apparatus comprising a pair of frames provided between upper and lower press plates of a press apparatus and provided to respectives of the upper and the lower press plates via packings for surrounding a predetermined space, an interpenetrated portion provided at one of the frames and capable of being interpenetrated into other of the frames movably in an up and down direction, a seal apparatus for slidably sealing an interval between the interpenetrated portion and the other of the frames, and a sucking apparatus for bringing a space surrounded by the interpenetrated portion and the other of the frames under a negative pressure, wherein the seal apparatus seals the interval by compensating for a strain of the interpenetrated portion caused by the negative pressure of the space.
It is preferable that the seal apparatus is a packing mounted to the interpenetrated portion and brought into sliding contact with an inner periphery of the other frame and includes a lip having a size in correspondence with the strain of the interpenetrated portion. Further, the seal apparatus may be a packing mounted to a side of the other frame and brought into sliding contact with an outer periphery of the interpenetrated portion.
According to the above-described constitution, the space formed by the frames can be expanded and contracted in the up and down direction and accordingly, can follow to a height of a work. Therefore, it is not necessary to prepare frames for respective height of the work. Further, the apparatus does not directly undergo press load and therefore, deformation or destruction thereof can be prevented. Further, the apparatus can effectively correspond to the strain caused by the negative pressure of the interpenetrated portion to thereby maintain the sealing function.
Further, there are achieved advantages that the apparatus can simply be attached to a conventional general purpose open press machine, a time period required for vacuuming is short since a volume of a vacuum chamber is necessary minimum in comparison with that of a house type vacuum press machine, the cost is low and so on.